JPH1164076A - Method for continuously operating weighing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continuously operate a weighing machine for weighing without stoppage, even when an abnormal weighing occurs due to the excessive or insufficient supply of an object to be weighed. SOLUTION: A weighing machine is continuously operated for weighing without stoppage, by continuing the weighing operations of the machine or reweighing an object to be measured by correcting a driving parameter, in accordance with the contents of abnormal weighing when the abnormal weighing occurs. When the weighing machine is used for weighing the proper amount of the object supplied from a vibrating trough by weighing the object a plurality of times, the number of weighing times and the time required until the proper amount is obtained in each weighing are found. The occurrence of the abnormal weighing due to the excessive supply of the object is discriminated from the nuntber of weighing times (steps S6 and 8) and the occurrence of another abnormal weighing due to the insufficient supply of the object is discriminated from the time required until the proper amount is obtained (steps S7 and 12). When the excessive supply occurs, the next weighing is performed by correcting the driving parameter of the vibrating trough based on the measuring time (steps S10 and 11) and, when the insufficient supply occurs, reweighing is performs by again sampling the object to be weighed (steps S13-17).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic weighing machine for automatic weighing of powders and granules, and more particularly, to a continuous weighing machine without stopping the weighing machine when an abnormality such as excessive amount or insufficient supply occurs during weighing. The present invention relates to a driving method for driving.

[0002]

2. Description of the Related Art A vibratory feeder-type weigher is known as a weigher for weighing powders and granules. FIG. 5 is a block diagram for explaining a configuration example of a conventional vibratory feeder type weighing machine. In FIG. 5, a vibrating feeder-type weighing machine supplies an object to be weighed, such as powder or granules, from a supply hopper 11 onto a vibrating trough 12, and the vibrator 17
And weighing hopper 1 through shutter 16
8, the object to be weighed in the weighing hopper 18 is quantitatively measured by the weighing sensor 19, and then discharged to the discharge chute 20.

[0003]

In the conventional weighing machine, when the object to be weighed is a highly adherent ash, a powder having a low specific gravity, or a material to be weighed having a high hygroscopic property, the object to be weighed is weighed. There is a problem that continuous weighing is difficult because the weighing body adheres to the contact surface.

[0004] Since the properties of powder and granules such as the moisture content of the object to be measured are large, there is a large difference in adhesion and fluidity when passing through a vibrating trough. Therefore, if the object to be weighed adheres to the contact surface on the path of the object to be weighed, such as the vibration trough of the vibration feeder, the weighing hopper, or the discharge chute, the flow characteristics of the powder deteriorate or the weighing accuracy decreases. It becomes difficult to stably perform continuous metering, and if the fluidity increases, an excessive amount will be supplied.

[0005] If such an excessive supply or insufficient supply of powders or granules occurs, accurate weighing cannot be performed. Therefore, in a conventional weighing machine, in such a case, it is determined that an abnormality has occurred and weighing is performed. The operation is temporarily stopped, and weighing conditions are set and used each time. Therefore, continuous operation of the weighing machine is difficult.

Therefore, the present invention solves the above-mentioned problems of the conventional weighing machine, and can continuously perform the weighing operation without stopping when an abnormality occurs due to excessive supply or insufficient supply of the object to be weighed. The purpose is to be able to do it.

[0007]

According to the continuous operation method of a weighing machine of the present invention, when a weighing error occurs, the drive parameters are corrected in accordance with the content of the error, and the weighing operation is continued or re-weighed. The weighing operation is performed continuously without stopping the weighing machine. The continuous operation method of the weighing machine of the present invention, in a weighing machine that weighs a positive amount by weighing the object to be weighed supplied by the vibrating trough a plurality of times,
For each weighing, determine the weighing time until the set amount is reached, and in multiple weighings, determine the number of weighings before the weighing is performed and the elapsed time until the weighing is completed. Then, the weighing abnormality of the supply shortage is determined based on the elapsed time to the correct amount, and in the case of the excess supply, the drive parameter of the vibration trough is corrected based on the measurement time to perform the next measurement, and in the case of the supply shortage, The object to be weighed is sampled again and weighed again.

[0008] In the continuous operation method of the weighing machine of the present invention, in order to determine the abnormality of the weighing and the content of the abnormality of oversupply or undersupply, the number of times of weighing until a positive amount is performed in a plurality of weighings. And the elapsed time until the correct amount is obtained, the metering abnormality is determined based on the number of times of weighing, and the insufficient metering abnormality is determined based on the elapsed time until the correct amount.

In the case of an oversupply, the rate of decrease of the measured value is small, and even if the number of times exceeds a preset number, the measured value exceeds the positive amount. As described above, when the number of times of weighing until the positive amount is performed exceeds the set number, it is determined that the supply is excessive. When the supply is insufficient, the weighing value is small, and a positive amount cannot be performed within a preset time. As described above, when the positive amount is not obtained within the set time, it is determined that the supply is insufficient.

In the case of abnormal measurement, the measurement is continued after the following processing. In the case of oversupply, the elapsed time up to the correct amount is obtained, the latest drive parameter of the vibration trough is corrected using this measurement time, and the next measurement is performed using the corrected drive parameter. If the supply is insufficient, the next drive parameter is obtained using the previous drive parameter,
The object to be weighed is sampled again according to the obtained drive parameters, and weighing is performed again.

Thus, even if a metering error such as an excessive supply or a shortage of supply occurs, the abnormality is detected and determined, and the weighing operation is continuously performed without stopping the weighing machine in response to the weighing error. You can do it.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 and 2 are block diagrams for explaining the outline of the weighing machine of the present invention. FIG.
FIG. 3 is a schematic block diagram for explaining functions of the weighing machine of the present invention. In FIG. 1, a sampler 6 samples an object to be weighed such as powder or granules from a supply source (not shown) and supplies the sampled object to a weighing machine 1. The control device 2 includes a system sequencer 5 that controls a sequence for moving the weighing machine 1 and the sampler 6, a determination unit 3 that determines an abnormality in the weighing performed by the weighing machine 1, and a driving parameter when a weighing abnormality is performed based on the determination result. Parameter calculation and setting means 4 for calculating and setting
Etc. are provided. It should be noted that the configuration of each of the above-described processing units may be arbitrarily determined by hardware or software.

In FIG. 2, a weighing machine 1 is a weighing machine provided with a vibrating feeder, and a supply hopper 11 converts a weighing object such as powder or granules supplied from a sampler 6 into a vibrating trough 12.
Supply on top. The vibrating trough 12 is vibrated by a vibrator (not shown), sends the object to be weighed to a weighing device 13 having a weighing sensor and a weighing hopper, weighs the object to be weighed, and discharges the weighed object quantitatively measured to a discharge shooter 14 or a weighing device. It is configured to discharge to the shooter 15.

Next, an example of the continuous operation method of the weighing machine of the present invention will be described with reference to the flowchart of FIG. 3 and the timing chart of FIG. In the following description,
An example in which a weighing hopper performs a positive amount and performs a weighing discharge operation of discharging the positive amount by the weighing hopper and a discharging operation of discharging a remaining amount or forcibly discharging the object to be weighed remaining after the weighing discharge operation. And

First, a set number n of weighing for judging an oversupply, a set time T for performing a positive quantity for judging a shortage of supply, and an allowable number m of re-weighing when the supply is insufficient are determined. (Step S1). After the setting, when a sampling start signal is instructed from the system sequencer 5 to the sampler 6 (FIG. 4A, (step S2))
The sampler 6 samples the object to be weighed such as powder or granules from the supply source and supplies the sample to the weighing machine 1 (Step S3). Thereafter, when a weighing start signal (FIG. 4B, (Step S4)) is sent from the system sequencer 5 to the weighing machine 1, the weighing machine 1 sends a drive signal to the weighing hopper to intermittently drive the vibration trough. Then, the processes of metering discharge, remaining amount discharge, and forced discharge are performed (FIG. 4C, (step S5)).

When the supply is normally performed, the weighing machine 1 performs a positive amount in the weighing and discharging. The metering discharge is performed by a plurality of preliminary discharges and a positive amount of discharge. In the initial stage of the supply, the supply amount of the object to be weighed is unstable, and the weighing value is not a positive amount in each of the weighing hopper drive signals (for example, 1 and 2) in FIG. Discharge without weighing. After the preliminary discharge is performed a plurality of times, when the supply amount of the object to be weighed is stabilized, the amount falls within a predetermined weighing error, and the weighing amount can be corrected. This positive amount is measured by a weighing sensor provided in the weighing hopper. In the case of the positive amount, the weighing sensor outputs a positive amount signal (FIG. 4D). If the output of the positive signal is continuous or the average is within a predetermined range, it is determined that a stable positive signal is being output, and the positive signal is output at the preset number p of weighing (FIG. 4 (e)). )) To output the correct amount of the object to be weighed from the weighing hopper.

In this step of driving the weighing hopper, it is determined whether the supply is excessive or insufficient.

The determination of the excess supply amount is made based on whether or not the number of times the positive amount signal is output is within a preset number of times n. The positive signal shown in FIG. 4F is output when the set number n has been exceeded. Therefore, the set number of times n
If a positive amount signal is not output at the point in time (step S6), it is determined that an over-metering abnormality has occurred, and an excess amount determination signal (FIG. 4 (g)) is output (step S8). .

The determination of the supply shortage is made based on whether or not the elapsed time from the start of the weighing until the output of the positive signal is within a set time T set in advance. FIG.
The positive signal shown in (h) is output when the set time T has been exceeded. Therefore, when the positive signal is output after the set time T has elapsed (step S7), it is determined that an insufficient supply weighing abnormality has occurred, and the shortage determination signal (FIG. 4 (i)) is output. (Step S12).

Next, the processing at the time of abnormal measurement will be described. If an excessive amount is determined in step S8, the following steps S9 to S11 are performed, and
When the shortage is determined in step 12, the weighing is continued by the following steps S13 to S18. Here, in the weighing operation, the current drive parameters of the vibration trough and the previous drive parameters are stored in the nonvolatile memory.

In the case of an excess amount determination, the latest drive parameters are read from the non-volatile memory (step S9), and a parameter calculation is performed using the drive parameters to obtain corrected drive parameters (step S10). Parameters are set in the weighing machine (step S11),
Weighing continues with the modified drive parameters.

In the case of a shortage determination, the previous drive parameter is read from the nonvolatile memory (step S1).
3) This drive parameter or a drive parameter having a higher strength than the drive parameter is obtained by performing parameter calculation (step S14), the obtained drive parameter is set in the weighing machine (step S15), and a resampling command is output. Then, the weighing operation from sampling is restarted again (step S16).

The number of command outputs for re-measurement is counted, and if the number exceeds the preset allowable number m of re-measurement when the supply is insufficient (step S1).
7) Display of sampler abnormality. This is to judge that the possibility of abnormality of the sampler, not of the weighing machine, is high when abnormality of supply shortage continues beyond the allowable number of times. By determining the allowable number of re-weighings, it is possible to distinguish between a weighing abnormality and a sampler abnormality (step S18).

In the determination of the excess amount, the correction of the drive parameters is performed in each weighing by obtaining a weighing time until the set weighing is reached, and the driving parameters are corrected using the weighing time as a parameter. In the case of overdose, the weighing time to reach the set weighing is shorter than the standard time, and the driving parameters for driving the vibration trough are determined to be large for performing the standard weighing. Modify the drive parameters of the vibration trough to approach standard time.

More specifically, the drive parameters can be corrected by setting the weighing time as a parameter in the weighing machine in accordance with the characteristics of the vibration trough. As a simple correction, for example, the amplitude intensity of the vibration trough can be switched stepwise, and the amplitude intensity can be set according to the ratio or difference between the magnitude of the weighing time and the standard time.

According to the embodiment of the present invention, in the case of abnormal weighing, weighing can be performed continuously without stopping the weighing operation. The set number of times and the set time can be arbitrarily changed according to the characteristics of the object to be weighed and the weighing machine.

According to the embodiment of the present invention, it is possible to distinguish between the oversupply amount and the undersupply abnormality,
Further, by changing the set value, it is possible to perform an abnormality determination corresponding to the object to be weighed. According to the embodiment of the present invention, it is possible to continuously perform weighing without stopping the weighing operation when the weighing is abnormal. According to the embodiment of the present invention, it is possible to distinguish between a weighing abnormality and a sampler abnormality.

[0028]

As described above, according to the continuous operation method of the weighing machine of the present invention, the weighing operation can be performed continuously without stopping the weighing machine.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram for explaining functions of a weighing machine of the present invention.

FIG. 2 is a block diagram schematically illustrating a weighing machine according to the present invention.

FIG. 3 is a flowchart illustrating an example of a continuous operation method of the weighing machine according to the present invention.

FIG. 4 is a timing chart for explaining an example of a continuous operation method of the weighing machine of the present invention.

FIG. 5 is a block diagram for explaining a configuration example of a conventional vibratory feeder type weighing machine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... weighing machine, 2 ... control device, 3 ... determination means, 4 ... parameter calculation and setting means, 5 ... system sequencer, 6 ... sampler, 11 ... supply hopper, 12 ... vibration trough, 13
... Measuring device, 14, 20 ... Discharge shooter, 15 ... Measurement shooter, 16 ... Shutter, 17 ... Vibrator, 18 ...
Weighing hopper, 19 ... weighing sensor.

Claims (1)

[Claims] 1. A weighing machine for weighing an object to be weighed supplied by a vibrating trough a plurality of times to weigh a positive amount,
For each weighing, determine the weighing time until the set amount is reached, and in multiple weighings, determine the number of weighings before the weighing is performed and the elapsed time until the weighing is completed. Then, the weighing abnormality of the supply shortage is determined based on the elapsed time to the correct amount, and in the case of the excess supply, the drive parameter of the vibration trough is corrected based on the measurement time and the next measurement is performed. Is a method for continuously operating a weighing machine, wherein reweighing is performed.